Abrading apparatus



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Oct. 12, 1937. J. A. KEENAN ABRADING APPARATUS Filed Aug. 29, 1935 g Lg P m. Z Y I I 5 I m FIE-l7 durability of an abrading machine and for eb- Patented Oct. 12, 1937 insane PATENT QFFEQE ABRADING APPARATUS John A. Keenan, New

American Optical YorkQN. Y., assignor to Company, Southbridge,

Mass, a voluntary association of Massachusetts Application August 29, 1935, Serial No. 38,417

3 Claims.

This invention relates to an abradinga'ppara 0n lenses or articles of a-similar nature. I

The principal object of the invention is to provide improved means for prolonging the life and viating obnoxious noises during its use.

Another object is to provide an attachment having means on the tool or work holding support which is subjected to the greatest amount of wear which maybe removed and replaced with a minimum of expense.

Another objectis to provide holding fingers on the tool or work holding support having means for reducingthe wear whereby the machine may be operated longer with a high degree of accuracy before replacement of the wearing parts of the fingers is necessary.

Other objects and advantages willbecome apparent from the following description taken in connection with the accompanying drawing and it will be apparent that many changes may be made in the details of construction and arrangement of parts Without departing from the spirit of the invention as expressed in the accompanying claims. I, therefore, do not wish to be limited to the exact details of construction and arrangement shown and described as the preferred form only has been shown by way of illustration.

Referring to the drawing:

Fig. I is a plan view of a tool or work holding support embodying the present invention;

Fig. II is a plan view of a modified form of the invention shown in Fig. I; 1

Fig. III is across section of a. holding finger along the line III-III of Fig. I;

Fig. IV is a cross section along the line IV-IV 0f Fig. II; and

Fig. V is a diagrammatic elevational View of 7 an abrading apparatus in which the invention is adapted to be used. v Abrading machines employed inthe produc- -tionfof 1enses having curved or difierent powof the lens will be of the shape and powerde sired. The most accurately operating arrangement for abrading such lenses has been found in i the past to be one formed 'with a pair of spaced .parallel upright supports pivoted diametricab lyopposite each other on the tool holder and provided with a work holder formed with a pair of horizontally disposed arms engaged between the diametrically opposed supports to hold the work against rotation in proper abrading relation with the tool. Although this type of attachment was very eflicient in the production of high grade lenses, it had a very serious drawback in that it soon became worn and impracticable for use.

Another serious defect in this type of attachment' was a tendency to produce a very displeasing and annoying noise during its use.

Since these upright supports and arms are constantly operated in sliding contact under fairly high pressure they soon became worn so badly that the accuracy of the apparatus became impaired. Various means have been suggested for reducing the wear on these parts. In some instances the arms. and/ or upright members have been provided with sleeves rotatably mounted so as to reduce the sliding contact wear on these parts. These sleeves must necessarily be round and, therefore, they engage on substantially a point contact which increases the pressure and the wear on these parts is not reduced as much as might be expected. These sleeves do, however, reduce the wear appreciably but still the replacement cost is rather high because of the sleeves being made of metal which is fairly expensive.

Accordingly, the main purpose of this invention is to reduce the wear whereby a greater accuracy is maintained, reduce the replacement cost and noise incident to the operation of these machines.

Broadly speaking, the invention contemplates means for providing bearing inserts in either side of the guiding fingers of the tool or work holding support which can be very quickly and easily replaced and which may be so arranged that a maximum of wear may be obtained with the replaceable bearing inserts.

Particularly referring to the drawing, an embodiment of the inventioncomprises a work holder I of the usual prior art type having diametrically opposed arms 2 which are adapted to be engaged between two spaced upright guiding members 3, only one of which is shown, pivotally connected to the opposite sides of a tool support 4 of the usualprior art abrading attachment. Any conventional means, shown in the form of a crank pin 6 actuated by driving means I, may be provided to move the tool relative to the work during the abrading operation. It is to be understood that during actuation of the work holder I carrying the work, such as the lens blank A, over the tool 8 the arms 2 will be caused to rock the spaced upright members 3 back and forth as well as oscillate in the direction of the axes of the arms 2. The sliding of the arms 2 against upright arms 3 causes great wear on these parts since they are operating under high pressure.

According to my invention suitable replaceable bearing inserts ID are fixedly held in recesses l I formed in the opposite sides of the arms 2. Since the work and work holder including the arms 2 must be frequently washed during the abrading operations, the inserts It must be capable of withstanding frequent immersions in water and still retain their wearing quality and still remain frictionally engaged in the recesses of the arms 2. For this reason, the inserts H] are preferably made of specially treated leather soaked in oil so that it is substantially waterproof and non absorbent. The inserts are pressed in and are frictionally held in the recesses H. The inserts are preferably square so that a large bearing surface is provided, whereby the bearing pressure is reduced and consequently wear is likewise reduced. Since the inserts are square, they may be inserted in the recesses so that after one side is worn, the inserts may be removed and reinserted so that another side is presented outwardly to serve as a bearing surface. If desired, the arms 2 may be made of round stock and the edges of the recesses may be peened over as at l3, see Fig. IV, to assist in maintaining the inserts in the recesses i I.

As shown in Fig. II, the inserts H1 may be made in sections l4, l5 and I6 as it will be readily understood that the middle portion l5 receives the greatest wear because of the movement of the tool or work holder I. I6 may be interchanged from time to time, thereby obtaining the maximum of wear from a given amount of bearing material. For example, when section l5 becomes worn, it may be removed and exchanged with section I4. When section M is worn, it may be exchanged with section l6. Each of these sections may be removed and reinserted to present a different surface as described above.

It is to be understood that the edgesof the recesses of the arms shown in Figs. I and III may be peened over to assist in holding the inserts I0. Also the inserts used in this modification may be divided into sections as shown in Fig. II.

Although specially treated leather has been found to be very satisfactory, any other suitable material, such as fiber or rubber, may be substituted for the leather. The inserts I!) may also be made of any suitable composition, such as felt impregnated with powdered graphite or other self lubricating material. The inserts l0 may also be made of suitable metal having free graphite to act as a self-lubricant. Any other suitable bearing metal may be used for the inserts [0.

The recesses Ii may also be formed wider at the bottom than at the top and the inserts may be complemental to the recesses so that they may be slipped in from the ends.

It may also be mentioned that the bearing inserts l0 may be placed in the uprights 3 as well These sections [4, I5, and

as, or instead of, in the arms 2 without departing from the spirit and scope of the invention.

From the foregoing description it will be apparent that I have provided a novel and improved attachment for abrading apparatus which greatly reduces the cost of replacement of wearing parts, maintains the accuracy and eliminates noise in operation.

Having described my invention, Iclaim:

1. An abrading apparatus having means for supporting a tool and means for guiding the work to be abraded over said tool, said means having normally related members engaging each other for holding the work in axial relation with the tool during the guiding of the work over said tool, one of said members having a groove extending longitudinally thereof on the side adapted to be engaged by the other member causing a portion of its cross section to assume a U shape and a replaceable bearing member of a semi-resilient material of a dimension slightly larger in cross section than the cross sectional area of the groove forced into said groove substantially throughout the length thereof and frictionally held in said groove along its longitudinal edges by the elastic after working of said material.

2. An abrading apparatus having means for supporting a tool and means for guiding the Work to be abraded over said tool, said means having normally related members engaging each other for holding the work in axial relation with the tool during the guiding of the Work over said tool, one of said members having a groove extending longitudinally thereof on the side adapted to be engaged by the other member causing a portion of its cross section to assume a U shape, one of the longitudinal edges of said grooved portion being deflected in a direction inwardly of the groove and a replaceable bearing member of a semi-resilient material forced inwardly of said groove and held therein by said deflected longitudinal edge and by friction created by the elastic after working of said material.

3. An abrading apparatus having means for supporting a tool and -means for guiding the Work to be abraded over said tool, said means having normally related members engaging each other for holding the work in axial relation with the tool during the guiding of the work over said tool, one of said members having a groove extending longitudinally thereof on the side adapted to be engaged by the other member causing a portion of its cross section to assume a U shape and a replaceable bearing member of a semiresilient material of a dimension slightly larger in cross section than the cross sectional area of the groove forced into said groove substantially throughout the length thereof and frictionally held in said groove along its longitudinal edges by the elastic after working of said material, said replaceable bearing member being divided into a plurality of sections whereby the section which receives the least wear during the abrading operation may be interchanged with the section which normally receives the greatest wear, whereby a maximum amount of wear can be obtained from a given amount of bearing material.

JOHN A. KEENAN. 

